Endoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision associated with endoscopic surgical techniques tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, stapler, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).
Endoscopic devices are passed through an access port, such as a trocar, to allow the distal end effector to engage tissue within a body cavity of a patient. With powered devices, any problems that occur may prevent removal of the device through the access port. For example, in the event the end effector becomes jammed during a firing stroke or the device otherwise fails, the end effector cannot be removed because tissue is engaged between the jaws. The surgeon may be forced to open up the patient and cut the instrument out of the patient, potentially causing serious harm to the patient.
Accordingly, methods and devices are needed to allow for removal of an instrument even upon failure of the instrument, especially retraction of any mechanisms that prevent the jaws of an end effector from opening and releasing clamped tissue.